This invention relates to a vacuum panel useful for load and non-load bearing walls of building structures.
Vacuum panels are old in the art and usually consist of a sandwich composed of a pair of exterior quadrangular sheets spaced apart by peripheral spacers and internal spacers and the assembly is rigidified by drawing a vacuum between the pair of sheets. It is known that one of the main problems faced by designers of vacuum panels is that the surface sheets of the panels tend to deform under strong vacuum and show the pattern of the interior supports that keep the exterior panel sheets from collapsing together when the vacuum is drawn. If such sheets are too light in gauge, the deformation by bending can reach a point of disfigurement and that requires expensive surface covering to hide the showing pattern results of the vacuum. If the sheets are of sufficiently heavy gauge initially to withstand the vacuum without deforming, then the panel becomes not only much more expensive, but also quite heavy for commercial use, especially in high-rise buildings where every ounce is counted. It is therefore of utmost importance that the design of the interior support structure not only resist heat transmission as much as possible, but also be designed in the optimum configuration to limit undesirable show through of interior support pattern to permit the use of the lightest possible gauge material. As the optimum configuration is being sought, the exterior support structure must be as rigid, yet as light as possible, while reducing heat transmission conduction as much as possible while retaining strength, impact resistance, and features that tend to low cost volume manufacture, with minimum tool cost and made from readily available materials. Quite obviously, the peripheral supports must meet the same design criteria and further be designed to rigidly support implosion pressures without special expensive and weight adding materials being put into the panel for this purpose. If the interior support structures are straight and contact the sheets in a straight line, then fold or crease lines will appear on the surface of the panels when the vacuum is pulled on the panels because, as it is well known, that sheet metal will crease in a straight line, when a curved crease, if possible, is not so readily created without much greater resistance. One prior art solution has been to construct the interior vacuum resisting supports in an egg crate configuration consisting of a plurality of vertical and horizontal members in plan view which are mutually supportive at their many junctions. One of the drawbacks with such a panel construction is this use of excessive material interiorly of the panel sheets because this crisscross internal structure provides unnecessary and excess support strength at intersection points in the panel where such support is unnecessary and the increased weight serves no purpose. The straight lines of the egg crate are more subject to crease deformation than curves.